The Caribbean island of Trinidad & Tobago is closing public schools and government offices as heavy thunderstorms approach the region.

The National Hurricane Center in Miami said the cluster is forecast to become a tropical storm by Monday night or early Tuesday.

TS Bret Forecast cone, June 19

TS Bret Forecast cone, June 19

NOAA

Officials said schools in Trinidad will close on Tuesday and that government offices in the sister island of Tobago also will be shuttered. Meteorologists warned of waves of more than 9 feet (3 meters) along the islands’ coasts.

Trinidad-based Caribbean Airlines canceled more than 30 flights on Monday.

A tropical storm watch has been issued for the nearby Dutch Caribbean islands of Bonaire, Curacao and Aruba.